1. Field of the Invention
This invention relates to an image sensor module, and more particularly to an image sensor module and a structure and method for manufacturing of wafer level package that can lower the cost, raise the yield and reliability.
2. Description of the Prior Art
The semiconductor technologies are developing very fast, and especially semiconductor dies have a tendency toward miniaturization. However, the requirements for the functions of the semiconductor dies have an opposite tendency to variety. Namely, the semiconductor dies must have more I/O pads into a smaller area, so the density of the pins is raised quickly. It causes the packaging for the semiconductor dies to become more difficult and decrease the yield.
The main purpose of the package structure is to protect the dies from outside damages. Furthermore, the heat generated by the dies must be diffused efficiently through the package structure to ensure the operation the dies.
The earlier lead frame package technology is already not suitable for the advanced semiconductor dies due to the density of the pins thereof is too high. Hence, a new package technology of BGA (Ball Grid Array) has been developed to satisfy the packaging requirement for the advanced semiconductor dies. The BGA package has an advantage of that the spherical pins has a shorter pitch than that of the lead frame package and the pins is hard to damage and deform. In addition, the shorter signal transmitting distance benefits to raise the operating frequency to conform to the requirement of faster efficiency. Most of the package technologies divide dies on a wafer into respective dies and then to package and test the die respectively. Another package technology, called “Wafer Level Package (WLP)”, can package the dies on a wafer before dividing the dies into respective dies. The WLP technology has some advantages, such as a shorter producing cycle time, lower cost, and no need to under-fill or molding.
The dies are, such as image sensor dies. Now, the image sensor module is formed by using a method of COB or LCC. The one drawback of the method of the COB is lower yield rate during packaging process due to particle contamination on sensing area. Besides, the drawbacks of the method of the LCC are higher packaging cost due to materials and lower yield rate during packaging process due to particle contamination on sensing area. Moreover, SHELL CASE company also develops wafer level package technique, the image sensor dies packaged by the SHELL CASE is higher cost due to requiring two glass plate and complicate process. And, the transparency is bad due to epoxy wearing out, and the potential reliability may be reduced.
Therefore, the present invention has been made in view of the above problems in the prior arts, and it is an objective of the present invention to provide a new image sensor module.